Commit | Line | Data |
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9f3acc31 AV |
1 | /* |
2 | * descriptor table internals; you almost certainly want file.h instead. | |
3 | */ | |
4 | ||
5 | #ifndef __LINUX_FDTABLE_H | |
6 | #define __LINUX_FDTABLE_H | |
7 | ||
9f3acc31 AV |
8 | #include <linux/posix_types.h> |
9 | #include <linux/compiler.h> | |
10 | #include <linux/spinlock.h> | |
11 | #include <linux/rcupdate.h> | |
12 | #include <linux/types.h> | |
21e54459 | 13 | #include <linux/init.h> |
2c666df8 | 14 | #include <linux/fs.h> |
21e54459 | 15 | |
60063497 | 16 | #include <linux/atomic.h> |
9f3acc31 AV |
17 | |
18 | /* | |
19 | * The default fd array needs to be at least BITS_PER_LONG, | |
20 | * as this is the granularity returned by copy_fdset(). | |
21 | */ | |
22 | #define NR_OPEN_DEFAULT BITS_PER_LONG | |
23 | ||
24 | /* | |
25 | * The embedded_fd_set is a small fd_set, | |
26 | * suitable for most tasks (which open <= BITS_PER_LONG files) | |
27 | */ | |
28 | struct embedded_fd_set { | |
29 | unsigned long fds_bits[1]; | |
30 | }; | |
31 | ||
32 | struct fdtable { | |
33 | unsigned int max_fds; | |
4d2deb40 | 34 | struct file __rcu **fd; /* current fd array */ |
9f3acc31 AV |
35 | fd_set *close_on_exec; |
36 | fd_set *open_fds; | |
37 | struct rcu_head rcu; | |
38 | struct fdtable *next; | |
39 | }; | |
40 | ||
1dce27c5 DH |
41 | static inline void __set_close_on_exec(int fd, struct fdtable *fdt) |
42 | { | |
43 | FD_SET(fd, fdt->close_on_exec); | |
44 | } | |
45 | ||
46 | static inline void __clear_close_on_exec(int fd, struct fdtable *fdt) | |
47 | { | |
48 | FD_CLR(fd, fdt->close_on_exec); | |
49 | } | |
50 | ||
51 | static inline bool close_on_exec(int fd, const struct fdtable *fdt) | |
52 | { | |
53 | return FD_ISSET(fd, fdt->close_on_exec); | |
54 | } | |
55 | ||
56 | static inline void __set_open_fd(int fd, struct fdtable *fdt) | |
57 | { | |
58 | FD_SET(fd, fdt->open_fds); | |
59 | } | |
60 | ||
61 | static inline void __clear_open_fd(int fd, struct fdtable *fdt) | |
62 | { | |
63 | FD_CLR(fd, fdt->open_fds); | |
64 | } | |
65 | ||
66 | static inline bool fd_is_open(int fd, const struct fdtable *fdt) | |
67 | { | |
68 | return FD_ISSET(fd, fdt->open_fds); | |
69 | } | |
70 | ||
9f3acc31 AV |
71 | /* |
72 | * Open file table structure | |
73 | */ | |
74 | struct files_struct { | |
75 | /* | |
76 | * read mostly part | |
77 | */ | |
78 | atomic_t count; | |
4d2deb40 | 79 | struct fdtable __rcu *fdt; |
9f3acc31 AV |
80 | struct fdtable fdtab; |
81 | /* | |
82 | * written part on a separate cache line in SMP | |
83 | */ | |
84 | spinlock_t file_lock ____cacheline_aligned_in_smp; | |
85 | int next_fd; | |
86 | struct embedded_fd_set close_on_exec_init; | |
87 | struct embedded_fd_set open_fds_init; | |
4d2deb40 | 88 | struct file __rcu * fd_array[NR_OPEN_DEFAULT]; |
9f3acc31 AV |
89 | }; |
90 | ||
af61b96b PM |
91 | #define rcu_dereference_check_fdtable(files, fdtfd) \ |
92 | (rcu_dereference_check((fdtfd), \ | |
7dc52157 | 93 | lockdep_is_held(&(files)->file_lock) || \ |
844b9a87 PM |
94 | atomic_read(&(files)->count) == 1 || \ |
95 | rcu_my_thread_group_empty())) | |
af61b96b PM |
96 | |
97 | #define files_fdtable(files) \ | |
98 | (rcu_dereference_check_fdtable((files), (files)->fdt)) | |
9f3acc31 | 99 | |
9f3acc31 AV |
100 | struct file_operations; |
101 | struct vfsmount; | |
102 | struct dentry; | |
103 | ||
104 | extern int expand_files(struct files_struct *, int nr); | |
105 | extern void free_fdtable_rcu(struct rcu_head *rcu); | |
106 | extern void __init files_defer_init(void); | |
107 | ||
108 | static inline void free_fdtable(struct fdtable *fdt) | |
109 | { | |
110 | call_rcu(&fdt->rcu, free_fdtable_rcu); | |
111 | } | |
112 | ||
113 | static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) | |
114 | { | |
115 | struct file * file = NULL; | |
116 | struct fdtable *fdt = files_fdtable(files); | |
117 | ||
118 | if (fd < fdt->max_fds) | |
af61b96b | 119 | file = rcu_dereference_check_fdtable(files, fdt->fd[fd]); |
9f3acc31 AV |
120 | return file; |
121 | } | |
122 | ||
123 | /* | |
124 | * Check whether the specified fd has an open file. | |
125 | */ | |
126 | #define fcheck(fd) fcheck_files(current->files, fd) | |
127 | ||
128 | struct task_struct; | |
129 | ||
130 | struct files_struct *get_files_struct(struct task_struct *); | |
131 | void put_files_struct(struct files_struct *fs); | |
132 | void reset_files_struct(struct files_struct *); | |
133 | int unshare_files(struct files_struct **); | |
02afc626 | 134 | struct files_struct *dup_fd(struct files_struct *, int *); |
9f3acc31 AV |
135 | |
136 | extern struct kmem_cache *files_cachep; | |
137 | ||
138 | #endif /* __LINUX_FDTABLE_H */ |